VDSL2 - slowly decreasing sync speeds inevitable?

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#154236 21-Oct-2014 20:46

So my sync rate seems to be gradually dropping in the 5 or so months since I moved from ADSL2 to VDSL.

I was getting around 40m/b to start with and as of tonight I am around 26

Annex Mode ANNEX_A
SNR Down 11.9 dB
SNR Up 25.1 dB
Line Attenuation Down 2.0 dB
Line Attenuation Up 102.3 dB
Data Rate Down 26856 kbps
Data Rate Up 10348 kbps
MAX Rate Down 36328 kbps
MAX Rate Up 17448 kbps
POWER Down 8.0 dbm
POWER Up 8.2 dbm

My stats look Ok as far as I can tell, so is this gradual decline just an inevitable part of VDSL2 as local contention increases?If this isn't expected behaviour, can I do much about it other than have Slingshot tech support go through the "reset the line/DLM" motions?

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#1159576 21-Oct-2014 20:46

Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

If you are posting regarding DSL speeds please check that

- you have reset your modem and router

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

- you are not being throttled by your ISP due to going over the monthly cap

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

- you read this topic and follow the instructions there.

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

- Your ISP and plan

- Type of connection (ADSL, ADSL2, VDSL)

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

- Your general location (or street)

- If you are rural or urban

- If you know your connection is to an exchange, cabinet or conklin

- If your connection is to a ULL or wholesale service

- If you have done an isolation test as per the link above

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

I recommend you read these two blog posts:

- Is your premises phone wiring impacting your broadband performance? (very technical)

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?

I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.

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Jase2985

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#1159595 21-Oct-2014 20:48

what was the attenuation when you had 40 down?

*you reformatted your post which made the info clearer*

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#1159598 21-Oct-2014 20:50

"Data rate" is 26 and download tests match that...

hio77

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Lizard Networks

#1159602 21-Oct-2014 20:53

2dB attenuation? is that a modem missreading?

26mbit is slow for 2dB..

Crosstalk is inevitable as connections become more common, that will contribute a drop in speed, yours seems more like a fault however.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

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#1159619 21-Oct-2014 20:58

hio77: 2dB attenuation? is that a modem missreading?

26mbit is slow for 2dB..

Seems to have been pretty consistently reporting as such! Not entirely sure I trust this Asus modem/router though!

I had a Chorus engineer come out about a month after the initial install and do the cabling properly as they had failed to do so the first time.

hio77: Crosstalk is inevitable as connections become more common, that will contribute a drop in speed, yours seems more like a fault however.

Hm...

Might be worth pushing their support again then.

RunningMan

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#1159630 21-Oct-2014 21:19

Item: My stats look Ok as far as I can tell, so is this gradual decline just an inevitable part of VDSL2 as local contention increases?

You've pretty much got it. As crosstalk and background noise increases from more connections in the same feeder the sync rate needs to drop to maintain the same 12dB noise margin.

Plenty of other people commenting on the same issue. ADSL has the same issue, just not as noticeable due to the lower frequencies used.

hio77

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Lizard Networks

#1159638 21-Oct-2014 21:42

Item:
Hm...

Might be worth pushing their support again then.

Ild ask them to simply double check what your downsteam attenuation is, on their side.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

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hio77

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Lizard Networks

#1159639 21-Oct-2014 21:42

Item:
Hm...

Might be worth pushing their support again then.

Ild ask them to simply double check what your downsteam attenuation is, on their side.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

NZCrusader

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#1159926 22-Oct-2014 12:07

List of options:
- Reboot router.
- Check / re-terminate cabling.
- Check / re-splice cabling to and from master filter.
- Contact SS and request a port reset.
- Check / re-splice cabling in roadside pedestal (grey pillar - must be done by chorus contractor).
- Re-termination at DSLAM (must be done by chorus contractor - sometimes they stuff this up the first time).

Further options for enhancement:
- Get a better modem (fritz box and dsl n66u seem to be highly rated on here).
- Tweak SNRM.
- Replace any old cable with new cat5e/6/6a.
- Ensure cable run uses shortest length possible, while also avoiding high levels of interference.

NZ / AU Battlefield 4 Gaming Community
http://www.sonsofvalour.net/forums/forum.php

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#1159935 22-Oct-2014 12:29

NZCrusader: List of options:

Thanks mate:

- Reboot router. - Done!
- Check / re-terminate cabling. Done last time engineer attended
- Check / re-splice cabling to and from master filter. Done last time engineer attended
- Contact SS and request a port reset. Will do today!
- Check / re-splice cabling in roadside pedestal (grey pillar - must be done by chorus contractor). Will check options here.
- Re-termination at DSLAM (must be done by chorus contractor - sometimes they stuff this up the first time). Will check options here.

Further options for enhancement:
- Get a better modem (fritz box and dsl n66u seem to be highly rated on here). Already using dsl n66u!
- Tweak SNRM. have tried before with limited success...although it seemed stable and did improve performance, it seemed to ultimately cause issues with DLM
- Replace any old cable with new cat5e/6/6a. Done last time engineer attended
- Ensure cable run uses shortest length possible, while also avoiding high levels of interference. Will check

NZCrusader

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#1160238 22-Oct-2014 18:46

Item:
NZCrusader: List of options:

Thanks mate:

- Reboot router. - Done!
- Check / re-terminate cabling. Done last time engineer attended
- Check / re-splice cabling to and from master filter. Done last time engineer attended
- Contact SS and request a port reset. Will do today!
- Check / re-splice cabling in roadside pedestal (grey pillar - must be done by chorus contractor). Will check options here.
- Re-termination at DSLAM (must be done by chorus contractor - sometimes they stuff this up the first time). Will check options here.

Further options for enhancement:
- Get a better modem (fritz box and dsl n66u seem to be highly rated on here). Already using dsl n66u!
- Tweak SNRM. have tried before with limited success...although it seemed stable and did improve performance, it seemed to ultimately cause issues with DLM
- Replace any old cable with new cat5e/6/6a. Done last time engineer attended
- Ensure cable run uses shortest length possible, while also avoiding high levels of interference. Will check

No problem.

Just to further elaborate, the cabling at the grey pillar is likely to have been spliced a long time ago, so having the tech cut it and re-splice may improve performance (did for me).

A port reset will cause DLM to run again (you may start off on a high profile and work from there, or it may be on a lower profile and work upwards).

Let us know how you get on.
However definitely on your attn. you should get a much better sync.

NZ / AU Battlefield 4 Gaming Community
http://www.sonsofvalour.net/forums/forum.php

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#1160594 23-Oct-2014 12:18

So Slingshot support seem to have been more sympathetic and helpful than previous occasions I have dealt with them which is promising!

They are treating as a "throughput" issue rather than a line issue..?

Have run some extended tests and they are processing now.

Interestingly:

1) They register the same 2db downstream attenuation as my modem
2) I get identical speeds using the OEM modem they provide
3) The slingshot testing seems to indicate that I should be getting around 47Mb based on the line quality and connection...but this obviously isn't happening!

Watch this space.

hio77

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#1160601 23-Oct-2014 12:49

Item: So Slingshot support seem to have been more sympathetic and helpful than previous occasions I have dealt with them which is promising!

They are treating as a "throughput" issue rather than a line issue..?

Have run some extended tests and they are processing now.

Interestingly:

1) They register the same 2db downstream attenuation as my modem
2) I get identical speeds using the OEM modem they provide
3) The slingshot testing seems to indicate that I should be getting around 47Mb based on the line quality and connection...but this obviously isn't happening!

Watch this space.

so that confirms no missreading thats good.

Honestly at your distance, i see no reason why your not sitting on 17a with a good 50+ down.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

webwat

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#1162158 25-Oct-2014 20:45

Its more of a crosstalk issue (interferance between neighbouring phone wires) than contention (competing for shared bandwidth on a busy uplink).

If the DSLAM wiring was a problem they should have fixed it already, but I would think near-end crosstalk affects everyone the same in that cabinet. Pillar wiring could be a dogs breakfast, but there is also possibly "multiples" on lines in your area (mid-span taps) that Chorus could fix.

This is one of the reasons that fibre is the long term solution for high speed communications...

Time to find a new industry!

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#1169174 5-Nov-2014 11:56

So after a promising start, we are now going round in circles or so it seems to me.

DLM reset did nothing, except now I am noticing an increase in CRC errors.

I called back today to follow up with support and the rep told me that everything I had been told up until now was incorrect re: my possible fault and line speed and that as it was a throughput error, there was no point in sending out a Chorus tech as it wouldn't be an issue with the physical cabling.

Next steps apparently is to plug the VB104W in for at least 24 hours to see what results that gives us.

Interestingly, both techs have asked me if I have two modems plugged in as they keep seeing multiple profiles/authentication attempts???

Suppose it may be my ASUS going screwy, so happy to test the original modem, but I don't seem to be able to get a consist opinion and no-one really wants to address the fact that my performance has always been well adrift of the potential of my line, going by the stats at least.

*sigh*

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